Lorentz变换的意义

在两条假设的基础上，用一种显而易见的方法推导出了洛伦兹变换，证明了时间坐标的洛伦兹变换是两个时间的和：一个与时间膨胀有关，另一个与光子从光源到接收器的飞行时间的相对性有关。     

洛伦兹变换的推导及对其悖论的解释

这两个坐标系的坐标该如何变换呢？其实这就是洛伦兹变换。在狭义相对论中,有一个公设和两个基本假设,所谓的公设是指在所有的参考系中,时空是均匀的;两个基本假设包括狭义相对性原理和光束不变原理。在推导洛伦兹变换的过程中,要用到矩阵等数学知识,这对于初学者会感到困难,本文运用基本的代数知识,从由一个公设和两个基本假设出发来推导出洛伦兹变换,并通过洛伦兹变换来解释一些由高中教材引起的悖论。     

关于向量模在坐标变换时的度量差异讨论

在经典物理学中,向量模的度量与绝对空间坐标相联系,与时间和坐标的变换是无关的。在近代物理学中,空间不再是与坐标变换无关的绝对空间,这一结论可由Lorentz(洛伦兹)变换式予以表征。这就是说,给定的向量模在变换的不同坐标系内去度量,其结果与度量方法有关。本文讨论的是对于同一向量模,在变换的笛卡尔坐标系与闵柯夫斯基坐标空间内     

压缩变换

在平面几何上有些与椭圆有关的问题,用压缩变换来解决则显得比较简单。 所谓压缩变换,就是将每个点P(x,y)变为另一个点P′(x′,y′),使得P点的横坐     

利用洛伦兹变换创建双标度时空坐标的设想

洛伦兹变换是建立在光速不变原理和狭义相对性原理两个假设的基础上,并引用了伽利略变换原理而得出的结论.因为光速和两惯性系的相对运动速度都是常数,所以,洛伦兹变换实质上就是在两个惯性系间进行的时间和空间的坐标变换.因为相对性原理的意义在于自然现象或物理形式对任何惯     

从一个自然时间实验看狭义相对论的错误

相对论认为运动的参照系中长度和时间会发生洛伦兹变换所预期的变化.通过一个理想的自然时间实验,从一个新的角度揭示了洛伦兹变换的自相矛盾,这种矛盾说明狭义相对论的两个基本假设——光速不变和物理规律不变——的确存在矛盾.     

关于间隔不变性与洛仑兹变换的几点注记

两个事件之间隔不变性(Δs )2=(Δs)2是狭义相对论的两个基本原理与时空的均匀性及空间各向同性之直接推论;间隔不变性(ds )2=(ds)2=-dx μdx μ=-dxμdxμ给出闵可夫斯基四维空间的度规,决定了狭义相对论的时空性质;由于洛仑兹变换可由间隔不变性直接推出,所以,洛仑兹变换及伽利略变换都是对两个事件之空间、时间坐标差Δxμ与Δx μ而言的;有时,利用间隔不变性讨论问题比利用洛仑兹变换更简便.     

当抛物线遭遇“交点”

我们知道,抛物线y=a（x-x1）（x-x2）（a≠0）必与x轴交于（x1,0）和（x2,0）两点.反之,若抛物线与x轴的两个交点的坐标分别为（x1,0）和（x2,0）,则可设所求抛物线的解析式为y=a（x-x1）（x-x2）（a≠0）,然后将图象上其它任意一点的坐标代入即可确定其解析式.一、＂交点＂为抛物线与x轴的交点例1已知抛物线经过原点及点（-1/2,-1/4）,且抛物线与x轴的另一交点到原点的距离为1,     

一次函数检测题

一、想一想，填一填(每小题3分，共24分) 1.到x轴、)轴的距离分别为3个、2个单位且在第二象限的点的坐标是2.在直角坐标系中，已知平行四边形的三个顶点的坐标为(O，O)、(4，o)、(2，2)，则第四个顶点的坐标是__. 3.在直角坐标系中，某一几何图形上一点的坐标为(3，2)，若将该图形横向和妙向分别平移2个、3个单位.则这点的对应点的坐标是_一_. _一醒戴娥署)莎蕊羊溉二二。、>0.贵蒸鹭旗;嚣体时的长度为__(?I。._ 8.如图2所不，关于、的一次函数:=k二+b的图象与若枯交于点(一2，o)，则关于x的不辱式瓜+b>O的解集是__.二、看一看，选一选(每…     

一种三角代换的推广

有些代数题可以用三角法来解。一、在某些与两个字母x、y的平方和x~2+y~2有关的问题中,设就可以把含x、y的代数式变换为含ρ、θ的三角式。这种代换实质上相当于把平面直角坐标系内的点的坐标     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.